1. Field of the Invention
The present invention relates to a foldable display apparatus, and more particularly, to a foldable display apparatus which is bent at a certain curvature or is unfolded to a flat state.
2. Discussion of the Related Art
A display apparatus using a flat display panel, such as a liquid crystal display (LCD) apparatus, a plasma display apparatus, an organic light emitting display apparatus, an electrophoretic display apparatus, or an electro-wetting display apparatus, is generally applied to notebook computers, portable electronic devices, televisions (TVs), and monitors.
Recently, even in portable electronic devices, the demand for a large screen is increasing, and thus, an apparatus including a display unit displaying a large screen is being developed and commercialized by connecting a flat display panel. In particular, foldable display apparatuses using the merits of a flexible display panel which is bendable or foldable provide portable convenience and include a display unit which displays a large screen, and thus are attracting much attention as next-generation technology of the display field. The foldable display apparatus may be applied to various fields such as TVs and monitors, in addition to portable electronic devices such as mobile communication terminals, electronic notes, e-books, portable multimedia players (PMPs), navigation devices, ultra mobile personal computers (PCs), mobile phones, smartphones, tablet PCs.
The foldable display apparatuses are disclosed, for example, in U.S. Patent Publication No. 2012/0044620. The mobile device disclosed in this patent publication unfolds a display with respect to a hinge having a link structure, thereby providing a large screen. However, since the mobile device disclosed in the patent publication cannot maintain a bending area of a folded display in a flat state due to an empty space between links of the hinge, the bending area of the unfolded display is pushed by external pressure, and for this reason, an image is distorted. Also, since the bending area of the display bent at a certain curvature with respect to the hinge is exposed to the outside, the bending area of the display is damaged by an external impact.